钢⁃UHPC组合梁高强螺栓剪力键抗剪性能试验研究

Experimental Study on Shear Resistance of High Strength Bolt Shear Key of Steel UHPC Composite Beam

为提升钢-混组合梁桥的轻质全装配化和后期更换的便利性,易拆卸螺栓剪力键与UHPC(超高性能混凝土)桥面板的组合方式及其协同工作性能值得探究。设计并制作了两组不同开孔构造的推出试件,研究钢-UHPC组合梁高强螺栓剪力键在竖向剪切荷载作用下的抗剪性能。试验结果表明:钢-UHPC推出试件表现为钢-混界面螺杆的剪断破坏,与钢-普通混凝土推出试件不同的是,破坏时嵌入螺母前方的承压混凝土未出现压碎脱落现象;相比于楔形开孔推出试件,阶梯形开孔构造对UHPC板相对于钢梁接触面的掀起行为具有更好的限制作用,其掀起位移终值比前者降低近14.5%;钢-UHPC比钢-普通混凝土推出试件滑移刚度提升约32.5%。

In order to improve lightweight and full assembly of steel-concrete composite girder bridges and the convenience of later replacement,the combination mode of easily removable bolt shear keys and UHPC(ultra-high performance concrete)bridge decks and their cooperative working performance are worth exploring.Two sets of push-out specimens with different opening structures were designed and fabricated to study the shear properties of high-strength bolt shear keys of steel UHPC composite beams under vertical shear loads.The test results show that the steel-UHPC push-out specimen exhibits the shear failure of the steel-concrete interface screw.Different from the steel-ordinary concrete push-out specimen,the pressure bearing concrete embedded in front of the nut doesn’t appear crushing and falling off when it is damaged.Compared with the wedge-shaped opening specimens,the stepped opening structure has a better limiting effect on the lifting behavior of UHPC plate relative to the steel beam contact surface,and the final lifting displacement of UHPC plate is reduced by nearly 14.5%compared with the former.The sliding stiffness of steel-UHPC is about 32.5%higher than that of steel-ordinary concrete push out specimens.